PHOTOMOD Raster File

PRF or MegaTIFF is an internal format of PHOTOMOD software for storing large
images.

This format was developed to store images larger than 4 GB.
As a basis for storing data used TIFF or JPEG2000 format.
Raster is split into fragments (tiles) such that each fragment
does not exceeded a predefined size (e.g., less than 1 GB).
An overview file also added to process raster data on a small scales.

PRF files has two variations: 'prf' for imagery data and 'x-dem' for elevation
data. Files can be georeferenced, but projection information can be stored only
in external files (*.prj).